1. Field of the Invention
The present invention relates to power systems and, more particularly to a discharge control apparatus arranged in a power conversion system.
2. Description of the Related Art
Conventionally, various types of power systems have been provided. For instance, a Japanese Patent No. 3289567 discloses a power system including a motor connected to an inverter unit in which a capacitor is connected between a pair of input terminals. The power system further includes a control unit which is adapted to control a discharging of the capacitor. Particularly, the control unit controls switching elements of the inverter unit such that the torque of the motor becomes approximately zero and reactive current flows through the motor. As a result, electric charge in the capacitor can be discharged (referred to discharging control).
In the discharge control, assuming the control unit operates the switching elements of the inverter unit differently from when the motor so is controlled normally (hereinafter refers to normal operation), the discharging control would not be used for normal operation. In other word, while it is in normal operation and the inverter unit is driven properly, the discharge control may not be performed correctly. Therefore, in this case, there is a concern that the control unit cannot perform the discharge control even if the discharge control is required.